function getXmlHttp(){
	if (window.XMLHttpRequest) {				
		xmlHttp = new XMLHttpRequest();
	} else {
		xmlHttp = new ActiveXObject('Microsoft.XMLHTTP');
	}
	
	return xmlHttp;
}

function doPost(sender){
	var oReq = getXmlHttp();
	var param = "";
	if(sender.data){
		for(var name in sender.data){
			var value = eval("sender.data." + name);
			param += "&" + name + "=" + encodeURI(value);
		}

		param = "?" + param.substring(1);
	}

	oReq.open("GET", sender.url + param, true);
	oReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
	oReq.send();
	oReq.onreadystatechange = function(){
		if (oReq.readyState == 4 && oReq.status == 200) {
			sender.success && sender.success(oReq.responseText);
		} else {
			sender.error && sender.error(oReq.status, oReq.responseText);
		}
	};
}